import java.util.Scanner;

public class wendu {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入温度");
        int num = sc.nextInt();
        double a = 32;
        double b = 5;
        double c = 9;
        System.out.println((num - a) * b / c);
    }
}
